Cutis

To the Editor:

Paraneoplastic acrokeratosis (PA), also known as Bazex syndrome, is a rare paraneoplastic dermatosis first described in 1965 by Bazex et al.¹ This entity is clinically characterized by dusky erythematous to violaceous keratoderma of the acral sites and commonly affects men older than 40 years. In most reported cases, there has been an underlying primary malignant neoplasm of the upper aerodigestive tract²; however, some other associated malignancies also have been reported. Skin changes tend to occur before the diagnosis of the associated tumor in 67% of cases. The cutaneous lesions usually resolve after successful treatment of the tumor and relapse in case of recurrence of the malignancy.³

A 53-year-old woman who was a smoker with no relevant medical background was referred to the dermatology department with an itching psoriasiform dermatitis on the palms and soles of 2 months' duration. There were no signs of systemic disease. Physical examination revealed well-demarcated, dusky red, thick, scaly plaques on the soles with sparing of the insteps (Figure, A). Scattered symmetric hyperkeratotic plaques were present on the palms (Figure, B). We also detected onychodystrophy on the hands. Other dermatologic findings were normal. Histologic examination of a biopsy specimen of the left sole showed hyperkeratosis, focal parakeratosis, acanthosis, hypergranulosis, and a predominantly perivascular dermal lymphocytic infiltrate.

With the diagnostic suspicion of PA, blood tests, chest radiograph, and colonoscopy were performed without revealing abnormalities. Positron emission tomography and computed tomography also was performed, showing cervical, mesenteric, retroperitoneal, and inguinal adenopathies. Histologic examination of both inguinal adenectomy and cervical lymph node biopsy revealed Bcl-2-positive in situ follicular lymphoma (ISFL). Examination of an iliac crest marrow aspirate showed minimal involvement of lymphoma (10%). Follow-up imaging performed 4 months after diagnosis showed no changes. The patient was diagnosed with a low-grade chronic lymphoproliferative disorder with histologic findings consistent with ISFL presenting with small disperse adenopathies and minimal bone marrow involvement. The hematology department opted for a wait-and-see approach with 6-month follow-up imaging.

The skin lesions were first treated with salicylic acid cream 10%, psoralen plus UVA therapy, and methotrexate 20 mg weekly for 2 months without remission. Replacing the other therapies, we initiated acitretin 25 mg daily, achieving sustained remission after 6 months of treatment, and then continued with a scaled dose reduction. The patient remained lesion free 1 year after starting the treatment, with a daily dose of 10 mg of acitretin.

Paraneoplastic acrokeratosis has been traditionally described as a paraneoplastic entity mainly associated with primary squamous cell carcinoma (SCC) of the upper aerodigestive tract or a metastatic SCC of the cervical lymph nodes with an unknown origin.^4,5 However, uncommon associations such as adenocarcinoma of the prostate, lung, esophagus, stomach, and colon; transitional cell carcinoma of the bladder; small cell carcinoma of the lung; cutaneous SCC; breast cancer; metastatic thymic carcinoma; metastatic neuroendocrine tumor; bronchial carcinoid tumor; SCC of the vulvar region; simultaneous multiple genitourinary tumors; and liposarcoma also have been described.⁶ Regarding the association with lymphoma, PA has been reported with peripheral T-cell lymphoma⁷ and Hodgkin disease⁸; however, ISFL underlying PA is rare.

Follicular lymphoma is the second most common non-Hodgkin lymphoma in Western countries and comprises approximately 20% of all lymphomas.⁹ It is slightly more prevalent in females, and the majority of patients present with advanced-stage disease. Generally considered to be an incurable disease, a watchful-waiting approach of conservative management has been advocated in most cases, deferring treatment until symptoms appear.⁹

Histology of PA is nonspecific, as in our case. However, it facilitates a differential diagnosis of major dermatoses including psoriasis vulgaris, pityriasis rubra pilaris, and lupus erythematosus.

Paraneoplastic palmoplantar keratoderma also is characteristic of Howel-Evans syndrome, which is a rare inherited condition associated with esophageal cancer. In contrast to our case, palmoplantar keratoderma in these patients usually begins around 10 years of age, is caused by a mutation in the RHBDF2 gene, and is inherited in an autosomal pattern.¹⁰

The diagnosis in our case was supported by a typical clinical picture, nonspecific histology, and the concurrent finding of the underlying lymphoma. Treatment of PA must focus on the removal of the underlying malignancy, which implies the remission of the cutaneous lesions. Taking into account that a recurrence of the primary tumor leads to a relapse of skin manifestations while distant metastases do not cause a reappearance of PA, it could be suggested that pathogenetically relevant factors are produced by the primary tumor and by lymph node metastases but not by metastases elsewhere.

In this case, due to the wait-and-see approach, a specific treatment for the skin lesions was established. Although management of the skin itself generally is ineffective, there are isolated reports of response after corticosteroids, antibiotics, antimycotics, keratolytic measures, or psoralen plus UVA therapy.⁶ Wishart¹¹ used etretinate to achieve an improvement of PA. We also achieved good response with acitretin. Retinoids are known to have antineoplastic activity, which may have been helpful in both the patient we presented and the one reported by Wishart.¹¹ In summary, we propose adding ISFL to the expanding list of malignant neoplasms associated with PA, noting the response of skin lesions after acitretin.

To the Editor:

Paraneoplastic acrokeratosis (PA), also known as Bazex syndrome, is a rare paraneoplastic dermatosis first described in 1965 by Bazex et al.¹ This entity is clinically characterized by dusky erythematous to violaceous keratoderma of the acral sites and commonly affects men older than 40 years. In most reported cases, there has been an underlying primary malignant neoplasm of the upper aerodigestive tract²; however, some other associated malignancies also have been reported. Skin changes tend to occur before the diagnosis of the associated tumor in 67% of cases. The cutaneous lesions usually resolve after successful treatment of the tumor and relapse in case of recurrence of the malignancy.³

A 53-year-old woman who was a smoker with no relevant medical background was referred to the dermatology department with an itching psoriasiform dermatitis on the palms and soles of 2 months' duration. There were no signs of systemic disease. Physical examination revealed well-demarcated, dusky red, thick, scaly plaques on the soles with sparing of the insteps (Figure, A). Scattered symmetric hyperkeratotic plaques were present on the palms (Figure, B). We also detected onychodystrophy on the hands. Other dermatologic findings were normal. Histologic examination of a biopsy specimen of the left sole showed hyperkeratosis, focal parakeratosis, acanthosis, hypergranulosis, and a predominantly perivascular dermal lymphocytic infiltrate.

With the diagnostic suspicion of PA, blood tests, chest radiograph, and colonoscopy were performed without revealing abnormalities. Positron emission tomography and computed tomography also was performed, showing cervical, mesenteric, retroperitoneal, and inguinal adenopathies. Histologic examination of both inguinal adenectomy and cervical lymph node biopsy revealed Bcl-2-positive in situ follicular lymphoma (ISFL). Examination of an iliac crest marrow aspirate showed minimal involvement of lymphoma (10%). Follow-up imaging performed 4 months after diagnosis showed no changes. The patient was diagnosed with a low-grade chronic lymphoproliferative disorder with histologic findings consistent with ISFL presenting with small disperse adenopathies and minimal bone marrow involvement. The hematology department opted for a wait-and-see approach with 6-month follow-up imaging.

The skin lesions were first treated with salicylic acid cream 10%, psoralen plus UVA therapy, and methotrexate 20 mg weekly for 2 months without remission. Replacing the other therapies, we initiated acitretin 25 mg daily, achieving sustained remission after 6 months of treatment, and then continued with a scaled dose reduction. The patient remained lesion free 1 year after starting the treatment, with a daily dose of 10 mg of acitretin.

Paraneoplastic acrokeratosis has been traditionally described as a paraneoplastic entity mainly associated with primary squamous cell carcinoma (SCC) of the upper aerodigestive tract or a metastatic SCC of the cervical lymph nodes with an unknown origin.^4,5 However, uncommon associations such as adenocarcinoma of the prostate, lung, esophagus, stomach, and colon; transitional cell carcinoma of the bladder; small cell carcinoma of the lung; cutaneous SCC; breast cancer; metastatic thymic carcinoma; metastatic neuroendocrine tumor; bronchial carcinoid tumor; SCC of the vulvar region; simultaneous multiple genitourinary tumors; and liposarcoma also have been described.⁶ Regarding the association with lymphoma, PA has been reported with peripheral T-cell lymphoma⁷ and Hodgkin disease⁸; however, ISFL underlying PA is rare.

Follicular lymphoma is the second most common non-Hodgkin lymphoma in Western countries and comprises approximately 20% of all lymphomas.⁹ It is slightly more prevalent in females, and the majority of patients present with advanced-stage disease. Generally considered to be an incurable disease, a watchful-waiting approach of conservative management has been advocated in most cases, deferring treatment until symptoms appear.⁹

Histology of PA is nonspecific, as in our case. However, it facilitates a differential diagnosis of major dermatoses including psoriasis vulgaris, pityriasis rubra pilaris, and lupus erythematosus.

Paraneoplastic palmoplantar keratoderma also is characteristic of Howel-Evans syndrome, which is a rare inherited condition associated with esophageal cancer. In contrast to our case, palmoplantar keratoderma in these patients usually begins around 10 years of age, is caused by a mutation in the RHBDF2 gene, and is inherited in an autosomal pattern.¹⁰

The diagnosis in our case was supported by a typical clinical picture, nonspecific histology, and the concurrent finding of the underlying lymphoma. Treatment of PA must focus on the removal of the underlying malignancy, which implies the remission of the cutaneous lesions. Taking into account that a recurrence of the primary tumor leads to a relapse of skin manifestations while distant metastases do not cause a reappearance of PA, it could be suggested that pathogenetically relevant factors are produced by the primary tumor and by lymph node metastases but not by metastases elsewhere.

In this case, due to the wait-and-see approach, a specific treatment for the skin lesions was established. Although management of the skin itself generally is ineffective, there are isolated reports of response after corticosteroids, antibiotics, antimycotics, keratolytic measures, or psoralen plus UVA therapy.⁶ Wishart¹¹ used etretinate to achieve an improvement of PA. We also achieved good response with acitretin. Retinoids are known to have antineoplastic activity, which may have been helpful in both the patient we presented and the one reported by Wishart.¹¹ In summary, we propose adding ISFL to the expanding list of malignant neoplasms associated with PA, noting the response of skin lesions after acitretin.

To the Editor:

Paraneoplastic acrokeratosis (PA), also known as Bazex syndrome, is a rare paraneoplastic dermatosis first described in 1965 by Bazex et al.¹ This entity is clinically characterized by dusky erythematous to violaceous keratoderma of the acral sites and commonly affects men older than 40 years. In most reported cases, there has been an underlying primary malignant neoplasm of the upper aerodigestive tract²; however, some other associated malignancies also have been reported. Skin changes tend to occur before the diagnosis of the associated tumor in 67% of cases. The cutaneous lesions usually resolve after successful treatment of the tumor and relapse in case of recurrence of the malignancy.³

A 53-year-old woman who was a smoker with no relevant medical background was referred to the dermatology department with an itching psoriasiform dermatitis on the palms and soles of 2 months' duration. There were no signs of systemic disease. Physical examination revealed well-demarcated, dusky red, thick, scaly plaques on the soles with sparing of the insteps (Figure, A). Scattered symmetric hyperkeratotic plaques were present on the palms (Figure, B). We also detected onychodystrophy on the hands. Other dermatologic findings were normal. Histologic examination of a biopsy specimen of the left sole showed hyperkeratosis, focal parakeratosis, acanthosis, hypergranulosis, and a predominantly perivascular dermal lymphocytic infiltrate.

With the diagnostic suspicion of PA, blood tests, chest radiograph, and colonoscopy were performed without revealing abnormalities. Positron emission tomography and computed tomography also was performed, showing cervical, mesenteric, retroperitoneal, and inguinal adenopathies. Histologic examination of both inguinal adenectomy and cervical lymph node biopsy revealed Bcl-2-positive in situ follicular lymphoma (ISFL). Examination of an iliac crest marrow aspirate showed minimal involvement of lymphoma (10%). Follow-up imaging performed 4 months after diagnosis showed no changes. The patient was diagnosed with a low-grade chronic lymphoproliferative disorder with histologic findings consistent with ISFL presenting with small disperse adenopathies and minimal bone marrow involvement. The hematology department opted for a wait-and-see approach with 6-month follow-up imaging.

The skin lesions were first treated with salicylic acid cream 10%, psoralen plus UVA therapy, and methotrexate 20 mg weekly for 2 months without remission. Replacing the other therapies, we initiated acitretin 25 mg daily, achieving sustained remission after 6 months of treatment, and then continued with a scaled dose reduction. The patient remained lesion free 1 year after starting the treatment, with a daily dose of 10 mg of acitretin.

Paraneoplastic acrokeratosis has been traditionally described as a paraneoplastic entity mainly associated with primary squamous cell carcinoma (SCC) of the upper aerodigestive tract or a metastatic SCC of the cervical lymph nodes with an unknown origin.^4,5 However, uncommon associations such as adenocarcinoma of the prostate, lung, esophagus, stomach, and colon; transitional cell carcinoma of the bladder; small cell carcinoma of the lung; cutaneous SCC; breast cancer; metastatic thymic carcinoma; metastatic neuroendocrine tumor; bronchial carcinoid tumor; SCC of the vulvar region; simultaneous multiple genitourinary tumors; and liposarcoma also have been described.⁶ Regarding the association with lymphoma, PA has been reported with peripheral T-cell lymphoma⁷ and Hodgkin disease⁸; however, ISFL underlying PA is rare.

Follicular lymphoma is the second most common non-Hodgkin lymphoma in Western countries and comprises approximately 20% of all lymphomas.⁹ It is slightly more prevalent in females, and the majority of patients present with advanced-stage disease. Generally considered to be an incurable disease, a watchful-waiting approach of conservative management has been advocated in most cases, deferring treatment until symptoms appear.⁹

Histology of PA is nonspecific, as in our case. However, it facilitates a differential diagnosis of major dermatoses including psoriasis vulgaris, pityriasis rubra pilaris, and lupus erythematosus.

Paraneoplastic palmoplantar keratoderma also is characteristic of Howel-Evans syndrome, which is a rare inherited condition associated with esophageal cancer. In contrast to our case, palmoplantar keratoderma in these patients usually begins around 10 years of age, is caused by a mutation in the RHBDF2 gene, and is inherited in an autosomal pattern.¹⁰

The diagnosis in our case was supported by a typical clinical picture, nonspecific histology, and the concurrent finding of the underlying lymphoma. Treatment of PA must focus on the removal of the underlying malignancy, which implies the remission of the cutaneous lesions. Taking into account that a recurrence of the primary tumor leads to a relapse of skin manifestations while distant metastases do not cause a reappearance of PA, it could be suggested that pathogenetically relevant factors are produced by the primary tumor and by lymph node metastases but not by metastases elsewhere.

In this case, due to the wait-and-see approach, a specific treatment for the skin lesions was established. Although management of the skin itself generally is ineffective, there are isolated reports of response after corticosteroids, antibiotics, antimycotics, keratolytic measures, or psoralen plus UVA therapy.⁶ Wishart¹¹ used etretinate to achieve an improvement of PA. We also achieved good response with acitretin. Retinoids are known to have antineoplastic activity, which may have been helpful in both the patient we presented and the one reported by Wishart.¹¹ In summary, we propose adding ISFL to the expanding list of malignant neoplasms associated with PA, noting the response of skin lesions after acitretin.

The Diagnosis: Trichofolliculoma

Microscopic examination revealed a dilated cystic follicle that communicated with the skin surface (Figure). The follicle was lined with squamous epithelium and surrounded by numerous secondary follicles, many of which contained a hair shaft. A diagnosis of trichofolliculoma was made.

Clinically, the differential diagnosis of a flesh-colored papule on the scalp with prominent follicle includes dilated pore of Winer, epidermoid cyst, pilar sheath acanthoma, and trichoepithelioma.^1,2 Multiple hair shafts present in a single follicle may be seen in pili multigemini, tufted folliculitis, trichostasis spinulosa, and trichofolliculoma. On histopathologic examination, a dilated central follicle surrounded with smaller secondary follicles was identified, consistent with trichofolliculoma.

Trichofolliculoma is a rare follicular hamartoma typically occurring on the face, scalp, or trunk as a solitary papule or nodule due to the proliferation of abnormal hair follicle stem cells.^3,4 It may present as a flesh-colored nodule with a central pore that may drain sebum or contain white vellus hairs. Trichofolliculoma is considered a benign entity, despite one case report of malignant transformation.⁵ Biopsy is diagnostic and no further treatment is needed. Recurrence rarely occurs at the primary site after surgical excision, which may be performed for cosmetic purposes or to alleviate functional impairment.

The Diagnosis: Trichofolliculoma

Microscopic examination revealed a dilated cystic follicle that communicated with the skin surface (Figure). The follicle was lined with squamous epithelium and surrounded by numerous secondary follicles, many of which contained a hair shaft. A diagnosis of trichofolliculoma was made.

Clinically, the differential diagnosis of a flesh-colored papule on the scalp with prominent follicle includes dilated pore of Winer, epidermoid cyst, pilar sheath acanthoma, and trichoepithelioma.^1,2 Multiple hair shafts present in a single follicle may be seen in pili multigemini, tufted folliculitis, trichostasis spinulosa, and trichofolliculoma. On histopathologic examination, a dilated central follicle surrounded with smaller secondary follicles was identified, consistent with trichofolliculoma.

Trichofolliculoma is a rare follicular hamartoma typically occurring on the face, scalp, or trunk as a solitary papule or nodule due to the proliferation of abnormal hair follicle stem cells.^3,4 It may present as a flesh-colored nodule with a central pore that may drain sebum or contain white vellus hairs. Trichofolliculoma is considered a benign entity, despite one case report of malignant transformation.⁵ Biopsy is diagnostic and no further treatment is needed. Recurrence rarely occurs at the primary site after surgical excision, which may be performed for cosmetic purposes or to alleviate functional impairment.

The Diagnosis: Trichofolliculoma

Microscopic examination revealed a dilated cystic follicle that communicated with the skin surface (Figure). The follicle was lined with squamous epithelium and surrounded by numerous secondary follicles, many of which contained a hair shaft. A diagnosis of trichofolliculoma was made.

Clinically, the differential diagnosis of a flesh-colored papule on the scalp with prominent follicle includes dilated pore of Winer, epidermoid cyst, pilar sheath acanthoma, and trichoepithelioma.^1,2 Multiple hair shafts present in a single follicle may be seen in pili multigemini, tufted folliculitis, trichostasis spinulosa, and trichofolliculoma. On histopathologic examination, a dilated central follicle surrounded with smaller secondary follicles was identified, consistent with trichofolliculoma.

Trichofolliculoma is a rare follicular hamartoma typically occurring on the face, scalp, or trunk as a solitary papule or nodule due to the proliferation of abnormal hair follicle stem cells.^3,4 It may present as a flesh-colored nodule with a central pore that may drain sebum or contain white vellus hairs. Trichofolliculoma is considered a benign entity, despite one case report of malignant transformation.⁵ Biopsy is diagnostic and no further treatment is needed. Recurrence rarely occurs at the primary site after surgical excision, which may be performed for cosmetic purposes or to alleviate functional impairment.

The Diagnosis: Grover Disease

Grover disease (also known as transient acantholytic dermatosis) was first described by Ralph W. Grover in 1970 as an idiopathic, acquired, monomorphous, papulovesicular eruption. Although originally characterized by solely transient acantholytic dermatosis, over time the term Grover disease has been expanded to include persistent acantholytic dermatoses. Grover disease chiefly affects white adults older than 40 years and is more prevalent in males than females. Cases generally are self-limited but correlate with age, as older adults are more likely to have prolonged eruptions.¹

Grover disease typically erupts with discrete, erythematous, edematous, acneform, red-brown or flesh-colored papules, papulovesicles, or keratotic papules that primarily are seen on the trunk and anterior portion of the chest. As the rash spreads, it can erupt on the neck and thighs. The etiology of Grover disease is unknown, but many factors have been associated with the condition in a limited number of patients, including exposure to UV radiation, excessive heat or sweating, use of sulfadoxine-pyrimethamine and recombinant human IL-4, and infection with Malassezia furfur and Demodex folliculorum.¹ Grover disease also has been associated with other conditions such as asteatotic eczema, allergic contact dermatitis, and atopic dermatitis.²

Histologically, Grover disease (Figure 1) is an acantholytic process that can exhibit dyskeratosis (corps ronds and grains). Foci often are small and multiple foci are seen on shave biopsy. There also may be spongiotic changes when associated with an eczematous element. A perivascular lymphohistiocytic infiltrate with eosinophils usually is seen.³ Basket weave keratin may be seen; however, as the lesions cause pruritus, erosions and ulcerations often are present.⁴

Grover disease has multiple histologic variants that may resemble Darier disease, Hailey-Hailey disease, pemphigus foliaceus, pemphigus vulgaris, and spongiotic dermatitis and can present in combination.⁵

The variant of Grover disease that has a Darier-like pattern is difficult to distinguish from Darier disease, an autosomal-dominant-inherited disorder classified by small papules that emerge in seborrheic areas during childhood and adolescence. Histologically, Darier disease (Figure 2) shows broad areas of dyskeratosis and acantholysis that lead to suprabasal cleavage. Follicular extension may be present. In addition, there often is prominent vertical parakeratosis in Darier disease.⁶ Histologic features that favor Darier disease over the Darier-like variant of Grover disease include a broad focus of acanthotic dyskeratosis with follicular extension; the presence of a hyperkeratotic stratum corneum; and a lack of spongiosis and eosinophils, which are notably absent in Darier disease but may be present in Grover disease.⁴

Another variant of Grover disease has a Hailey-Hailey-like pattern, which is characterized by Hailey-Hailey disease's dilapidated brick wall appearance or the diffuse suprabasal acantholysis of all epidermal layers without notable dyskeratosis.⁴ Hailey-Hailey disease, also known as familial benign pemphigus, is an autosomal-dominant disorder that presents with erythematous vesicular plaques in flexural areas. The plaques progress to flaccid bullae with rupture and crusting and spread peripherally.⁷ Pathology shows suprabasilar clefts and numerous acantholytic cells (Figure 3). Dyskeratotic keratinocytes are rare with infrequent corps ronds and rare grains. The epidermis also is less hyperplastic in Grover disease than in Hailey-Hailey disease.¹

Grover disease also may present histologically with a pemphiguslike pattern, mimicking pemphigus foliaceus and pemphigus vulgaris; however, direct immunofluorescence studies are negative in Grover disease.

Pemphigus foliaceus is an autoimmune disorder caused by autoantibodies to desmoglein 1, which are present on the surfaces of keratinocytes, and is characterized by scaly crusts and blisters.⁸ Histologically, pemphigus foliaceus (Figure 4) shows a superficial epidermal blistering process. The acantholysis may be subtle and is commonly localized to the stratum granulosum, extending into the stratum corneum. Complete loss of the stratum corneum can be seen, resulting in only scattered acantholytic cells. Spongiosis also may be seen. The dermis shows a perivascular infiltrate that often contains eosinophils. Pemphigus foliaceus is confirmed by direct immunofluorescence.⁹

Pemphigus vulgaris is an autoimmune blistering disorder that is characterized by IgG autoantibodies to desmoglein 3, a component of desmosomes that are involved in keratinocyte-to-keratinocyte adhesion. Clinically, patients present with flaccid fragile blisters on the skin and mucous membranes that rupture easily, leading to painful erosions.¹⁰ Intraepidermal blisters are seen histologically (Figure 5) with the loss of cohesion (acantholysis) seen classically in the lower portions of the epidermis where desmoglein 3 is most prominent. When only the basal layer remains, the histology has been likened to a tombstone row.¹¹ Extension of the blister along the adnexa is common. The underlying dermis shows a perivascular infiltrate with eosinophils. Early lesions may show only eosinophilic spongiosis. Direct immunofluorescence studies show IgG and C3 in an intercellular pattern that resembles a fish net or chicken wire.^4,11

The spongioticlike pattern of Grover disease is marked by epidermal edema with separation of the keratinocytes and the revelation of their intracellular bridges,⁴ which manifests as vesiculation in the stratum corneum or upper layers of the epidermis.¹²

Grover disease is self-limited and may spontaneously resolve; however, the disease may be responsive to topical and systemic steroids. Additionally, avoidance of aggravating factors such as sunlight, heat, and sweating can improve symptoms.²

The Diagnosis: Grover Disease

Grover disease (also known as transient acantholytic dermatosis) was first described by Ralph W. Grover in 1970 as an idiopathic, acquired, monomorphous, papulovesicular eruption. Although originally characterized by solely transient acantholytic dermatosis, over time the term Grover disease has been expanded to include persistent acantholytic dermatoses. Grover disease chiefly affects white adults older than 40 years and is more prevalent in males than females. Cases generally are self-limited but correlate with age, as older adults are more likely to have prolonged eruptions.¹

Grover disease typically erupts with discrete, erythematous, edematous, acneform, red-brown or flesh-colored papules, papulovesicles, or keratotic papules that primarily are seen on the trunk and anterior portion of the chest. As the rash spreads, it can erupt on the neck and thighs. The etiology of Grover disease is unknown, but many factors have been associated with the condition in a limited number of patients, including exposure to UV radiation, excessive heat or sweating, use of sulfadoxine-pyrimethamine and recombinant human IL-4, and infection with Malassezia furfur and Demodex folliculorum.¹ Grover disease also has been associated with other conditions such as asteatotic eczema, allergic contact dermatitis, and atopic dermatitis.²

Histologically, Grover disease (Figure 1) is an acantholytic process that can exhibit dyskeratosis (corps ronds and grains). Foci often are small and multiple foci are seen on shave biopsy. There also may be spongiotic changes when associated with an eczematous element. A perivascular lymphohistiocytic infiltrate with eosinophils usually is seen.³ Basket weave keratin may be seen; however, as the lesions cause pruritus, erosions and ulcerations often are present.⁴

Grover disease has multiple histologic variants that may resemble Darier disease, Hailey-Hailey disease, pemphigus foliaceus, pemphigus vulgaris, and spongiotic dermatitis and can present in combination.⁵

The variant of Grover disease that has a Darier-like pattern is difficult to distinguish from Darier disease, an autosomal-dominant-inherited disorder classified by small papules that emerge in seborrheic areas during childhood and adolescence. Histologically, Darier disease (Figure 2) shows broad areas of dyskeratosis and acantholysis that lead to suprabasal cleavage. Follicular extension may be present. In addition, there often is prominent vertical parakeratosis in Darier disease.⁶ Histologic features that favor Darier disease over the Darier-like variant of Grover disease include a broad focus of acanthotic dyskeratosis with follicular extension; the presence of a hyperkeratotic stratum corneum; and a lack of spongiosis and eosinophils, which are notably absent in Darier disease but may be present in Grover disease.⁴

Another variant of Grover disease has a Hailey-Hailey-like pattern, which is characterized by Hailey-Hailey disease's dilapidated brick wall appearance or the diffuse suprabasal acantholysis of all epidermal layers without notable dyskeratosis.⁴ Hailey-Hailey disease, also known as familial benign pemphigus, is an autosomal-dominant disorder that presents with erythematous vesicular plaques in flexural areas. The plaques progress to flaccid bullae with rupture and crusting and spread peripherally.⁷ Pathology shows suprabasilar clefts and numerous acantholytic cells (Figure 3). Dyskeratotic keratinocytes are rare with infrequent corps ronds and rare grains. The epidermis also is less hyperplastic in Grover disease than in Hailey-Hailey disease.¹

Grover disease also may present histologically with a pemphiguslike pattern, mimicking pemphigus foliaceus and pemphigus vulgaris; however, direct immunofluorescence studies are negative in Grover disease.

Pemphigus foliaceus is an autoimmune disorder caused by autoantibodies to desmoglein 1, which are present on the surfaces of keratinocytes, and is characterized by scaly crusts and blisters.⁸ Histologically, pemphigus foliaceus (Figure 4) shows a superficial epidermal blistering process. The acantholysis may be subtle and is commonly localized to the stratum granulosum, extending into the stratum corneum. Complete loss of the stratum corneum can be seen, resulting in only scattered acantholytic cells. Spongiosis also may be seen. The dermis shows a perivascular infiltrate that often contains eosinophils. Pemphigus foliaceus is confirmed by direct immunofluorescence.⁹

Pemphigus vulgaris is an autoimmune blistering disorder that is characterized by IgG autoantibodies to desmoglein 3, a component of desmosomes that are involved in keratinocyte-to-keratinocyte adhesion. Clinically, patients present with flaccid fragile blisters on the skin and mucous membranes that rupture easily, leading to painful erosions.¹⁰ Intraepidermal blisters are seen histologically (Figure 5) with the loss of cohesion (acantholysis) seen classically in the lower portions of the epidermis where desmoglein 3 is most prominent. When only the basal layer remains, the histology has been likened to a tombstone row.¹¹ Extension of the blister along the adnexa is common. The underlying dermis shows a perivascular infiltrate with eosinophils. Early lesions may show only eosinophilic spongiosis. Direct immunofluorescence studies show IgG and C3 in an intercellular pattern that resembles a fish net or chicken wire.^4,11

The spongioticlike pattern of Grover disease is marked by epidermal edema with separation of the keratinocytes and the revelation of their intracellular bridges,⁴ which manifests as vesiculation in the stratum corneum or upper layers of the epidermis.¹²

Grover disease is self-limited and may spontaneously resolve; however, the disease may be responsive to topical and systemic steroids. Additionally, avoidance of aggravating factors such as sunlight, heat, and sweating can improve symptoms.²

The Diagnosis: Grover Disease

Grover disease (also known as transient acantholytic dermatosis) was first described by Ralph W. Grover in 1970 as an idiopathic, acquired, monomorphous, papulovesicular eruption. Although originally characterized by solely transient acantholytic dermatosis, over time the term Grover disease has been expanded to include persistent acantholytic dermatoses. Grover disease chiefly affects white adults older than 40 years and is more prevalent in males than females. Cases generally are self-limited but correlate with age, as older adults are more likely to have prolonged eruptions.¹

Grover disease typically erupts with discrete, erythematous, edematous, acneform, red-brown or flesh-colored papules, papulovesicles, or keratotic papules that primarily are seen on the trunk and anterior portion of the chest. As the rash spreads, it can erupt on the neck and thighs. The etiology of Grover disease is unknown, but many factors have been associated with the condition in a limited number of patients, including exposure to UV radiation, excessive heat or sweating, use of sulfadoxine-pyrimethamine and recombinant human IL-4, and infection with Malassezia furfur and Demodex folliculorum.¹ Grover disease also has been associated with other conditions such as asteatotic eczema, allergic contact dermatitis, and atopic dermatitis.²

Histologically, Grover disease (Figure 1) is an acantholytic process that can exhibit dyskeratosis (corps ronds and grains). Foci often are small and multiple foci are seen on shave biopsy. There also may be spongiotic changes when associated with an eczematous element. A perivascular lymphohistiocytic infiltrate with eosinophils usually is seen.³ Basket weave keratin may be seen; however, as the lesions cause pruritus, erosions and ulcerations often are present.⁴

Grover disease has multiple histologic variants that may resemble Darier disease, Hailey-Hailey disease, pemphigus foliaceus, pemphigus vulgaris, and spongiotic dermatitis and can present in combination.⁵

The variant of Grover disease that has a Darier-like pattern is difficult to distinguish from Darier disease, an autosomal-dominant-inherited disorder classified by small papules that emerge in seborrheic areas during childhood and adolescence. Histologically, Darier disease (Figure 2) shows broad areas of dyskeratosis and acantholysis that lead to suprabasal cleavage. Follicular extension may be present. In addition, there often is prominent vertical parakeratosis in Darier disease.⁶ Histologic features that favor Darier disease over the Darier-like variant of Grover disease include a broad focus of acanthotic dyskeratosis with follicular extension; the presence of a hyperkeratotic stratum corneum; and a lack of spongiosis and eosinophils, which are notably absent in Darier disease but may be present in Grover disease.⁴

Another variant of Grover disease has a Hailey-Hailey-like pattern, which is characterized by Hailey-Hailey disease's dilapidated brick wall appearance or the diffuse suprabasal acantholysis of all epidermal layers without notable dyskeratosis.⁴ Hailey-Hailey disease, also known as familial benign pemphigus, is an autosomal-dominant disorder that presents with erythematous vesicular plaques in flexural areas. The plaques progress to flaccid bullae with rupture and crusting and spread peripherally.⁷ Pathology shows suprabasilar clefts and numerous acantholytic cells (Figure 3). Dyskeratotic keratinocytes are rare with infrequent corps ronds and rare grains. The epidermis also is less hyperplastic in Grover disease than in Hailey-Hailey disease.¹

Grover disease also may present histologically with a pemphiguslike pattern, mimicking pemphigus foliaceus and pemphigus vulgaris; however, direct immunofluorescence studies are negative in Grover disease.

Pemphigus foliaceus is an autoimmune disorder caused by autoantibodies to desmoglein 1, which are present on the surfaces of keratinocytes, and is characterized by scaly crusts and blisters.⁸ Histologically, pemphigus foliaceus (Figure 4) shows a superficial epidermal blistering process. The acantholysis may be subtle and is commonly localized to the stratum granulosum, extending into the stratum corneum. Complete loss of the stratum corneum can be seen, resulting in only scattered acantholytic cells. Spongiosis also may be seen. The dermis shows a perivascular infiltrate that often contains eosinophils. Pemphigus foliaceus is confirmed by direct immunofluorescence.⁹

Pemphigus vulgaris is an autoimmune blistering disorder that is characterized by IgG autoantibodies to desmoglein 3, a component of desmosomes that are involved in keratinocyte-to-keratinocyte adhesion. Clinically, patients present with flaccid fragile blisters on the skin and mucous membranes that rupture easily, leading to painful erosions.¹⁰ Intraepidermal blisters are seen histologically (Figure 5) with the loss of cohesion (acantholysis) seen classically in the lower portions of the epidermis where desmoglein 3 is most prominent. When only the basal layer remains, the histology has been likened to a tombstone row.¹¹ Extension of the blister along the adnexa is common. The underlying dermis shows a perivascular infiltrate with eosinophils. Early lesions may show only eosinophilic spongiosis. Direct immunofluorescence studies show IgG and C3 in an intercellular pattern that resembles a fish net or chicken wire.^4,11

The spongioticlike pattern of Grover disease is marked by epidermal edema with separation of the keratinocytes and the revelation of their intracellular bridges,⁴ which manifests as vesiculation in the stratum corneum or upper layers of the epidermis.¹²

Grover disease is self-limited and may spontaneously resolve; however, the disease may be responsive to topical and systemic steroids. Additionally, avoidance of aggravating factors such as sunlight, heat, and sweating can improve symptoms.²